A road finishing machine may be used in practice for docking to a truck for material transfer. In the process, it is important that no jerky accelerations are transmitted from the material supply vehicle to the road finishing machine, which could lead to damages in the paving. Consequently, in practice road finishing machines are employed which comprise a pushing device at their chassis in front, seen in the paving direction, by which they may cushion the docking of a material supply vehicle.
The applicant's EP 2 527 534 A1 discloses a road finishing machine with a pushing device movably mounted at the chassis which preferably comprises at least one friction spring as absorbing member. With the latter, the shock-absorption of a truck that docks to it works well, while it turned out that an absorber unit including a friction spring is expensive.
DE 10 2011 120 161 A1 discloses a road finishing machine with a pushing device movably mounted to the chassis, the pushing device being spring-mounted by at least one elastomer structural absorbing body. A disadvantage of this, however, consists in that the elastomer structural absorbing body gets easily soiled and may embrittle by heat or insolation prevailing on the construction site. Once the elastomer structural absorbing body is embrittled, its absorbing properties will also deteriorate.
U.S. Pat. No. 5,004,394 A discloses a road finishing machine having a pushing device mounted to it which, according to a first embodiment, is mounted in an absorbing manner relative to the chassis of the road finishing machine by means of a leaf spring. In another embodiment, the pushing device is fixed to two hydraulic cylinders. The hydraulic cylinders are each connected to a hydraulic circuit which supplies a hydraulic medium to the hydraulic cylinders from outside or which withdraws the hydraulic medium from the hydraulic cylinders. A disadvantage of this consists in that the hydraulic circuit has a complex design and requires a lot of space on the road finishing machine. Moreover, the components employed in the hydraulic circuit, e.g., the hydraulic pump or the control valves, must be serviced at regular intervals. Such a pushing device is expensive to manufacture and difficult to be retrofitted at existing road finishing machines.